Chaeles moeeill



(No Model.)

I 0. MORRILL.

JOINT FOR DIVIDERS AND GALIPERS.

No. 284,045. Patented Aug. 28, 1883.

CHARLES MORRILL,

PATENT OFFICE.

OF NEWV YORK, N. Y

JOINT FOR DIVIDERS AND CALIP ERS.

SPECIFICATION forming part of Letters Patent NO. 284,045, dated August 28, 1883.

Application filed August 19, 1882. (No model.) I

To all whom it may concern Be it known that I, CHARLES MORRILL, of New York city, have invented certain new and useful Improvements in Dividers, Calipers, &c., of which the following is a specification.

My invention applies to the joint or hinge of dividers or similar instruments, and it aims to provide a simple and efficient means of tightening the same, which will enable the points to be held firmly at any desired measurement to which they may be set, and which will admit of taking up its own wear, so as to constantly keep the hinge-j oint tight, notwithstanding the wear of constant use.

The invention consists in the peculiar construction and combination of parts, as hereinafter described and claimed.

In the drawings, Figure 1 presents a front elevation of a dividers provided with my improvement. Fig. 2 is a longitudinal section on x a: through the center of the hinge. Fig. 3 is aside elevation.

Inthe drawings, a a indicate the legs of the dividers, one end of each of which tapers, as usual, to a fine point, while the opposite ends thereof are formed to engage with each other, like the leaves of a hinge, in substantially the usual way-that is, the leg a, on which the female part of the hinge is formed, is mortised or slit at the end to receive the tenon b on the end of the male leg a. I prefer to make the members of the hinge-that is, the mortised and tenoned partsof a broad circular shape, as shown best in Fig. 1, instead of the narrow angular form usually employed, so as to obtain greater strength and a broader frictional bearing and render the form more symmetrical. I also prefer to form the periphery of the tenon with a knurled bead, c, projecting beyond the periphery of the mortised part d, which improves the appearance; but these details are not essential. Now, through the center of the engaged tenon and mortise of the hinge is formed a bore or pivot-hole, as seen best in Fig. 2, which is very much larger than usual, and is of a conical or wedging form, and in this large conical bore is fitted a friction-cone or large wedging-pintle, f, from the narrow end of which projects a screw-stem, g, on which is engaged a thumb-nut, h, which may be screwed down upon the face of the mortise part of the hinge, so as to thus draw the friction cone or pintle into the conical bore, and at the same time force the faces of tenon and mortise closely together, thus tightening the joint in a. very efficient manner. The conical pintle f is of such a length, diameter, and taper that when it is brought to a bearing in its conical socket the base end of the cone will protrude slightly from one ex- 6o ternal face of the hinge, while the narrow end will not quite reach the opposite outer face, as seen in Fig. 2, thus leaving the wedge a certain range of wear to permit its advance in the socket, according as the surfaces wear away during constant use, as will be readily understood. Between the under side of the nut and the face of the hinge a washer, i, is preferably interposed, and this washer may be either free to turn, or it may have projecting points or lugs to engage with recesses in the end of the conical pintle f, or vice versa, so as to prevent the washer from turning. A non-rotary washer is preferable, but not essential.

The thumb-nut or rotary knob h is a little smaller in diameter than the diameter of the hinge members, as shown best in Fig. 1-, and its periphery is preferably rounded and deeply knurled, as represented in Figs. 1 and 3, to afford a good grasp in turning the nut or knob one way or the other. I also preferably form the knob with a recessed center on the top side from which the knurled rim rises, and I prefer to nick the upper side of this rim withv a series of square-edged radial notches, m m, as shown well in Figs. 1 and 2. It will therefore be seen that the raised knurled rim affords a good grasp for the fingers in turning the nut one way or the other, and when it is desired to screw down the nut very tightly the nicks m m will afford engagement for a small pry or wrench, which may be in the form of a simple piece of wire or a stout nail, thus obtaining in a simple way a powerful leverage to turn the nut or knob.

Instead of forming the knob h as a nut turning on a screw projecting from the cone f, the relation may be'reversed, and the hub of the knob may be formed with the screw to screw into the cone with substantially the same ef- IOO fect.

It will now be seen that by this form of clamp-joint I produce a compound action in tightening the hinge which is very effective, for not only are the flat faces of the members of the hinge forced into close frictional contact, as in the ordinary joint, but in addition to this the pivotal cone f is wedged into the pivot-bore through the members 'of the hinge, which wedging action obviously produces a much more powerful frictional adherence than can be obtained by the contact of flat surfaces, as heretofore. The improved joint is thus not only tightened very firmly, but also in a quick and easy manner, and sufficient range of wear is provided for long and constant use.

This will obviate the annoyance of having the legs or points of the instrument easily shifted or moved when set to a certain position, and it will prevent the loosening of .the joint by constant use. At the same time the construction is simple and inexpensive.

I am aware that the use of tapering plugs adapted for-use in joints, as in {shill-couplings, is not broadly new with me, and such construction is not sought to be covered in this other to afford means for taking up-the wear and adjusting the friction of the joint, substantially as and for the purpose set forth.

. CHAS. MORRILL.

Witnesses GHAs. M. HIGGINS, JNo. E. GAVIN. 

